Removing the master and slave language

[bopopescu]

For diversity reasons, it would be nice to try to avoid 'master' and 'slave' terminology in this repository which can be associated to slavery. The master-slave terminology could be problematic for people in several countries which has the history of slavery like Romania, USA and many others. Thank you for considering the proposal. Let me know if any changes in the PR are needed, I would be happy to implement them.

[ChrisWakefield]

Thank you for the pull request @bopopescu.
While I don't disagree with your intent, it appears that all of the changes you propose are in the google-cloud-sdk api. In other words, these are in a library that we use but did not create. The right place to request these changes is with the google-cloud-sdk. Have you already done this?

If we change our copy of this library but Google does not change theirs, the next time we get an updated version all of our changes will be reversed.

In the meantime, we will review our use of this library, and simply remove it entirely if that is a viable option. Note that old versions of the files still remain in the repository.